Excessive drowsiness or daytime sleepiness is an adverse effect of certain medications, including nonsteroidal anti-inflammatory drugs (NSAIDs), sedatives, sedative-antidepressants, analgesics, opioids, barbiturates, anticonvulsants, antipsychotics, chemotherapy agents, antihypertensives, antibiotics, antivirals, antihistamines, and benzodiazepines. Combined drugs that cause drowsiness (eg, opioids and benzodiazepines, or other central nervous system depressants) can be life-threatening, as they may depress respiration and cause death.

Management includes medication adjustments or substitutions, lower dosage, slower titration, avoidance of concurrent medications known to cause drowsiness, and allowing several weeks for patients to develop tolerances for medication. Patient conditions such as dehydration and metabolic imbalances can magnify the somnolence caused by medications. A number of medications, including psychostimulants and caffeine, have been found to counteract the symptom of drowsiness in some patients.